JP2001011483A - Aqueous operational liquid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which is excellent in lubricity, thermal stability and oxidation stability by blending a specific amount of a polyether-monol or a polyether-polyol obtained by reacting ethylene oxide and a monoepoxide having a specific number of carbon atoms with a compound containing an active hydrogen atom using a combined metal cyanide complex as a catalyst. SOLUTION: A composition is obtained by blending 5-30 pt.wt., against 100 pts.wt. of the composition, of a polyether-monol or a polyether-polyol having a molecular weight of 4,000-40,000 obtained by reacting a monoepoxide having not less than 3 carbon atoms. As a monoepoxide having not less than 3 carbon atoms, propylene oxide, 1,2-butylene oxide 2,3-butylene oxide and isobutylene oxide are preferable. A preferable blending ratio of ethylene oxide and a monoepoxide having not less than 3 carbon atoms is 3/7-9/1 in weight. The reaction temperature is preferably 30-180 deg.C. The pressure at the reaction is preferably not more than 5 kg/cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an aqueous hydraulic fluid composition used for a machine tool such as a press machine. More specifically, an aqueous hydraulic fluid composition using a polyether monool or a polyether polyol obtained by reacting a mixture of ethylene oxide and a monoepoxide having 3 or more carbon atoms with an active hydrogen-containing compound using a double metal cyanide complex as a catalyst About.

[0002]

^2. Description of the Related Art In a hydraulic device of a press machine, since a pressure of 50 to 300 kgf / cm ² G is normally applied by a hydraulic pump, leakage of hydraulic fluid easily occurs in a hydraulic pump portion and a hydraulic cylinder portion. Friction occurs on the sliding surface. In order to prevent this, the working fluid needs to have an appropriate kinematic viscosity and lubricity, and an aqueous working fluid composition mainly containing water and low molecular weight glycols is generally used. If the kinematic viscosity or lubricity is insufficient with a working fluid containing only water and low molecular weight glycols as main components, polyether monool or polyether obtained by reacting ethylene oxide and propylene oxide with alcohols is used. A working fluid containing a polyol is used. These aqueous hydraulic fluid compositions are classified into flame retardant types because they contain a large amount of water.

Heretofore, polyether monools or polyether polyols used in these working fluids have been produced by addition polymerization of alkylene oxides using potassium hydroxide, sodium hydroxide or the like as a catalyst. In order to reduce the friction coefficient of polyether monools or polyether polyols having high molecular weights and kinematic viscosities, it has been required.

[0004] In order to reduce unsaturated monool by-produced in increasing the molecular weight of polyether monool or polyether polyol, a method using a catalyst other than potassium hydroxide and sodium hydroxide has been proposed. JP-A-10-218986 discloses a hydraulic oil composition using a polyether monool or a polyether polyol obtained by reacting an active hydrogen atom-containing compound with an alkylene oxide using an alkali metal catalyst comprising a mixture of cesium and rubidium. Has been proposed.

[0005] However, although the kinematic viscosity and the coefficient of friction of the working fluid are effective, there is a problem that the characteristics are insufficient in terms of oxidation stability and thermal stability. In other words, in addition to the kinematic viscosity and friction characteristics, the working fluid is required to be able to withstand long-term use without generating corrosive acids or sludge due to heat and oxidative deterioration, and all these characteristics are fully satisfied. There was nothing to make.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous hydraulic fluid composition having excellent lubricity, heat stability and oxidation stability.

[0007]

That is, the present invention provides a compound having at least one active hydrogen atom (hereinafter referred to as an active hydrogen-containing compound) as an initiator in the presence of a double metal cyanide complex catalyst and ethylene oxide and a compound having 3 carbon atoms. A polyether monool or a polyether polyol having a number average molecular weight of 4000 to 40,000 obtained by reacting the mixture with the above monoepoxide is mixed with an aqueous hydraulic fluid composition 10
An aqueous hydraulic fluid composition containing 5 to 30 parts by weight per 0 parts by weight.

It is considered that the double metal cyanide complex catalyst used in the present invention has a structure represented by the following formula (1). M _a [M ′ _x (CN) _y ] _b (H ₂ O) _c (R) _d (1) where M is Zn (II), Fe (II), Fe (III),
Co (II), Ni (II), Al (III), Sr (II),
Mn (II), Cr (III), Cu (II), Sn (II),
Pb (II), Mo (IV), Mo (VI), W (IV), W
(VI), etc., and M ′ is Fe (II), Fe (III),
Co (II), Co (III), Cr (II), Cr (III),
Mn (II), Mn (III), Ni (II), V (IV), V
(V), R is an organic ligand, a, b, x and y are positive numbers depending on the valence and coordination number of the metal, and c and d are positive numbers depending on the coordination number of the metal. Is the number of

In the formula (1), M is preferably Zn (II), and M ′ is Fe (II), Fe (III), Co (II), C (II).
o (III) is preferred. Examples of the organic ligand include ketone, ether, aldehyde, ester, alcohol, amide and the like, and ether and alcohol are preferable. As the ether, ethylene glycol dimethyl ether (glyme), diethylene glycol dimethyl ether (diglyme) and the like are preferable, and as the alcohol, t-butanol, t-butyl cellosolve and the like are preferable.

The double metal cyanide complex catalyst represented by the formula (1) is a metal salt MX _a (M and a are the same as those described above; X is M
Anion to form a salt with. ) And polycyanometallate (salt) _Ze [ _M'x (CN) _y ] _f (M ', x, and y are the same as described above. Z is hydrogen, an alkali metal, an alkaline earth metal, and the like. E and f are A positive integer determined by the valence and coordination number of Z and M '), or a mixed solvent of water and an organic solvent is mixed, and an organic ligand R is added to the obtained double metal cyanide. It is prepared by removing excess solvent and organic ligand R after contact.

Polycyanometallate (salt) _Ze [M '
_x (CN) _y ] _f can be hydrogen, an alkali metal or other various metals for Z, and is preferably a lithium salt, a sodium salt, a potassium salt, a magnesium salt, or a calcium salt. Particularly preferred are ordinary alkali metal salts, ie, sodium and potassium salts.

The active hydrogen-containing compound used as an initiator in the present invention includes, for example, methanol, ethanol, isopropyl alcohol, butanols and the like.
Dihydric alcohols, dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol and 1,4-butanediol, trihydric alcohols such as glycerin, trimethylolpropane and hexanetriol, pentaerythritol, diglycerin Alcohols having a valency of 4 or more, sugars such as sorbitol, sucrose, methylglucoside, aliphatic amines such as ethylenediamine, aromatic amines such as toluylenediamine, diphenylmethanediamine, and alkanolamines such as triethanolamine and diethanolamine. , Bisphenol A,
Phenols such as resole and novolak, and other hydroxy compounds can be used.

Further, polyethers having a lower molecular weight than the target compound obtained by reacting the above compound with a monoepoxide such as an alkylene oxide can also be used. It is particularly preferred to use such low molecular weight polyethers.
In this case, low molecular weight polyethers having a molecular weight of 500 to 1500 are particularly preferred. These active hydrogen-containing compounds may be used alone or in combination of two or more.

The monoepoxide having 3 or more carbon atoms used in the present invention includes propylene oxide, 1,2
Preferred is at least one selected from -butylene oxide, 2,3-butylene oxide and isobutylene oxide. These monoepoxides may be used alone or in combination of two or more.

The mixing ratio of ethylene oxide and monoepoxide having 3 or more carbon atoms (hereinafter referred to as a monoepoxide mixture of ethylene oxide and monoepoxide having 3 or more carbon atoms) is defined as the weight ratio of ethylene oxide / monoepoxide having 3 or more carbon atoms. Is preferably 3/7 to 9/1, and particularly preferably 4/6 to 8/2.

The polyether monool or polyether polyol in the present invention is usually produced by reacting a mixture of a monoepoxide mixture and an active hydrogen-containing compound as an initiator in the presence of a double metal cyanide complex catalyst. Further, the reaction can be carried out while gradually adding the monoepoxide mixture to the reaction system.

In the above reaction, the reaction temperature is 30 to 180.
C is preferable, and 90 to 130 C is more preferable. Further, the pressure during the reaction is preferably at most 5 kg / cm ² or less. The maximum reaction pressure when reacting the monoepoxide mixture is 5
If it exceeds kg / cm ² , it is not preferable because by-products are easily generated.

The amount of the catalyst used is not particularly limited, but is suitably about 1 to 5000 ppm, more preferably 20 to 1000 ppm, based on the active hydrogen-containing compound used. The catalyst may be introduced into the reaction system in a lump at first, or may be divided and introduced sequentially.

After completion of the reaction, the polyether monool or polyether polyol may be used as it is, but it is preferable to carry out purification such as removal of the catalyst. As a method for removing the catalyst, a method described in the above-mentioned known document can be employed. For example, there is a method in which after deactivating the catalyst by adding an alkali, the deactivated catalyst component and the alkali are treated with an adsorbent or an ion-exchange resin and removed by filtration or the like.

The number average molecular weight of the polyether monol or polyether polyol is 4000 to 40,000. Particularly preferably, it is 8,000 to 35,000, most preferably, 10,000 to 30,000. When the number average molecular weight of the polyether monol or polyether polyol is lower than 4000, the effect of reducing friction with the face material is reduced. When the number average molecular weight is higher than 40,000, the kinematic viscosity is too high.

The resulting polyether monol or polyether polyol has an oxyethylene group content of 3
0% by weight or more, preferably 40 to 80% by weight
Is particularly preferred. The oxyethylene group content refers to the total of both the oxyethylene group caused by the initiator and the one caused by ethylene oxide reacted in the presence of the double metal cyanide complex catalyst.

The amount of the polyether monool or polyol used in the present invention is 5 to 30 parts by weight, preferably 8 to 25 parts by weight, more preferably 10 to 20 parts by weight, per 100 parts by weight of the aqueous hydraulic fluid composition. It is. If the amount is less than 5 parts by weight, the kinematic viscosity required for the working fluid becomes low. On the other hand, when the amount is more than 30 parts by weight, the kinematic viscosity of the aqueous hydraulic fluid composition increases and the fluidity decreases.

An example of the formulation of the aqueous hydraulic fluid composition of the present invention is as follows: 35 to 50% by weight of water, 5 to 30% by weight of the polyether monol or polyether polyol referred to in the present invention, 50% by weight, oil improver 0-10% by weight, rust inhibitor 0-5% by weight, pH adjuster,
The antifoaming agent, antioxidant, anti-coloring agent and sequestering agent are each 0 to 2% by weight.

Examples of the low molecular weight glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, hexylene glycol, dihexylene glycol, trihexylene glycol and the like. These may be used alone or in combination of two or more. The molecular weight of low molecular weight glycols is 100
0 or less is preferable.

Examples of the oiliness improver include aliphatic carboxylic acids such as decanoic acid, oleic acid and isostearic acid, aromatic carboxylic acids such as benzoic acid and dimethylbenzoic acid, and alkali metal salts thereof.

As a rust inhibitor, monoethanolamine,
Triethanolamine, ethylenediamine, diethylenetriamine, cyclohexylamine, morpholine, 1,
Examples thereof include organic amines such as 4-bis-2-aminoethylpiperazine, 2-heptadecyl-1- (2-hydroxyethyl) imidazoline and dimethylaminoethanol, and alkylene oxide adducts of the above organic amines.

Examples of the pH adjuster include the above-mentioned organic amines and hydroxides of alkali metals. In some cases, the pH adjuster can be used also as an oiliness improver or a rust inhibitor. As the defoaming agent, a silicone-based defoaming agent is usually used. Examples of the antioxidant include benzotriazole, mercaptobenzimidazole, mercaptobenzothiazole and the like. Coloring inhibitors include basic dyes and acid dyes. Examples of the sequestering agent include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and oxycarboxylic acids such as gluconic acid and tartaric acid, and derivatives thereof (particularly, metal salts). These may be used alone or in combination of two or more.

[0028]

EXAMPLES The present invention will be specifically described below with reference to Examples (Examples 1 to 3) and Comparative Examples (Examples 4 to 6), but the present invention is not limited to these Examples. Parts indicate parts by weight. In addition, polyols A to polyether polyols
The number average molecular weight of F was calculated from the measured number of functional groups and hydroxyl value of the initiator.

(Production of double metal cyanide complex catalyst) A zinc hexacyanocobaltate-glyme complex (catalyst A) was prepared according to the method described in US Pat. No. 4,477,589.

Example 1 A hydroxyl value 168 (unit: mgKOH / g) obtained by reacting a mixture of propylene oxide / ethylene oxide (weight ratio 35/65) with glycerin.
g, the same applies hereinafter) of 50 parts of polyether polyol a),
Add 0.20 part of Catalyst A to the autoclave,
With propylene oxide / ethylene oxide (weight ratio 3
5/65) of the mixture (763 parts) at a gauge pressure of about 4-5 kg
/ Cm ² . Subsequently, aging was performed at the same temperature until no decrease in internal pressure was observed. After the completion of the reaction, the catalyst was removed to obtain polyol A. The hydroxyl value of polyol A was 11.1.

(Example 2) 25 of polyether polyol a
Parts, 0.20 part of catalyst A were added to the autoclave, and 10 parts
At 0 ° C., 767 parts of a mixture of propylene oxide / ethylene oxide (weight ratio: 35/65) are added at a gauge pressure of about 4 to 5 parts.
It was continuously supplied so as to keep the pressure at kg / cm ² . Subsequently, aging was performed at the same temperature until no decrease in internal pressure was observed.
After completion of the reaction, the catalyst was removed to obtain polyol B. The hydroxyl value of polyol B was 5.84.

Example 3 20 parts of polyether polyol b having a hydroxyl value of 500 and 0.21 part of catalyst A obtained by reacting sorbitol with propylene oxide were added to an autoclave, and propylene oxide / ethylene oxide was added at 100 ° C. 1017 parts of a mixture (weight ratio 35/65) were continuously supplied at a gauge pressure of about 4 to 5 kg / cm ² . Subsequently, aging was performed at the same temperature until no decrease in internal pressure was observed. After completion of the reaction, the catalyst was removed to obtain polyol C. The hydroxyl value of polyol C was 14.0.

(Example 4) 50 of polyether polyol a
Then, 13.28 parts of a 50% aqueous cesium hydroxide solution were added to the autoclave, and dehydration was performed at 120 ° C. under a reduced pressure of 10 mmHg for 2 hours. Thereafter, 780 parts of a mixture of propylene oxide / ethylene oxide (weight ratio 35/65) was continuously supplied at 95 ° C. at a gauge pressure of about 4 to 5 kg / cm ² . Subsequently, aging was performed at the same temperature until no decrease in internal pressure was observed. After completion of the reaction, the catalyst was removed to obtain polyol D. The hydroxyl value of polyol D was 11.3.

(Example 5) 50 of polyether polyol a
And 2.67 parts of 98% potassium hydroxide were added to the autoclave, and dehydration was performed at 120 ° C. under a reduced pressure of 10 mmHg for 2 hours. Then, at 95 ° C, propylene oxide /
Mixture 824 of ethylene oxide (35/65 by weight)
The parts were continuously supplied at a gauge pressure of about 4 to 5 kg / cm ² . Subsequently, aging was performed at the same temperature until no decrease in internal pressure was observed. After completion of the reaction, the catalyst was removed to obtain polyol E. The hydroxyl value of polyol E is 11.3.
Met.

(Example 6) 20 of polyether polyol b
And 4.65 parts of a 50% aqueous solution of cesium hydroxide in an autoclave.
Dehydration was performed for hours. Thereafter, at 95 ° C., 1036 parts of a mixture of propylene oxide / ethylene oxide (weight ratio 35/65) was continuously supplied at a gauge pressure of about 4 to 5 kg / cm ² . Subsequently, aging was performed at the same temperature until no decrease in internal pressure was observed. After completion of the reaction, the catalyst was removed to obtain polyol F. The hydroxyl value of polyol F was 14.2.

Each of the polyols A to F obtained in Examples 1 to 6
5 parts, dipropylene glycol 43 parts, oleic acid 1.
An aqueous working fluid composition was prepared from 2 parts, 0.8 parts of monoethanolamine and 40 parts of water, and the appearance and kinematic viscosity (unit:
mm ² / s). Next, Test 1 and Test 2 were performed. Table 1 shows the results.

(Test 1) Oxidation stability test Rotating cylinder type oxidation stability test method (JIS K251)
The test was performed at a test temperature of 120 ° C. according to 4). Appearance and kinematic viscosity of the aqueous hydraulic fluid composition after the test (test time: 4 hours), and change rate of kinematic viscosity before and after the test (unit:%)
Was measured. The rate of change of the kinematic viscosity is (change rate) =
It was determined by (kinematic viscosity after test-kinematic viscosity before test) / (kinematic viscosity before test). (Test 2) Thermal Stability Test An autoclave (SUS316, 500 ml) was filled with 400 ml of the aqueous hydraulic fluid composition and held at 200 ° C. for 200 hours. The appearance and kinematic viscosity of the aqueous hydraulic fluid composition after the test, and the rate of change (unit:%) of the kinematic viscosity before and after the test were measured.

[0038]

[Table 1]

[0039]

According to the present invention, in the presence of a double metal cyanide complex catalyst,
By using a polyether monool or a polyether polyol obtained from the reaction of a mixture of ethylene oxide and a monoepoxide having 3 or more carbon atoms as a working fluid, a product excellent in lubricity, heat stability, and oxidation stability can be obtained. Was.

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Claims (3)

[Claims] A compound having at least one active hydrogen atom as an initiator is reacted with a mixture of ethylene oxide and a monoepoxide having 3 or more carbon atoms in the presence of a double metal cyanide complex catalyst to obtain a number average molecular weight. 4000
An aqueous hydraulic fluid composition comprising 5 to 30 parts by weight of a polyether monool or polyether polyol of up to 40,000 per 100 parts by weight of the aqueous hydraulic fluid composition. 2. The aqueous hydraulic fluid according to claim 1, wherein the monoepoxide having 3 or more carbon atoms is at least one selected from propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, and isobutylene oxide. Composition. 3. The mixture weight ratio of ethylene oxide / monoepoxide having 3 or more carbon atoms in the mixture of ethylene oxide and monoepoxide having 3 or more carbon atoms is 3/7 to 9/1.
The aqueous hydraulic fluid composition according to claim 1 or 2, wherein